Nanoarchitecture and dynamics of the mouse enteric glycocalyx examined by freeze-etching electron tomography and intravital microscopy

Author(s)

Sun, Willy W. ^{[1, 2]} ; Krystofiak, Evan S. ^{[1, 3]} ; Leo-Macias, Alejandra ^{[1, 3]} ; Cui, Runjia ^{[1, 3]} ; Sesso, Antonio ^[4] ; Weigert, Roberto ^{[1, 5]} ; Ebrahim, Seham ^[5] ; Kachar, Bechara ^{[1, 3]}

Affiliation

^[1] NIDCD, Lab Cell Struct & Dynam, NIH, Bethesda, MD 20892 - USA

^[2] Univ Maryland, Neurosci & Cognit Sci Program, College Pk, MD 20740 - USA

^[3] Ebrahim, Seham, NCI, Lab Cellular \& Mol Biol, NIH, Bethesda, MD 20892 USA.Sun, Willy W., NIDCD, Lab Cell Struct & Dynam, NIH, Bethesda, MD 20892 - USA

^[4] Univ Sao Paulo, Inst Trop Med, Sect Struct Biol, BR-05403 Sao Paulo, SP - Brazil

^[5] NCI, Lab Cellular & Mol Biol, NIH, Bethesda, MD 20892 - USA

• Document type: Journal article
• Source: COMMUNICATIONS BIOLOGY; v. 3, n. 1 JAN 7 2020.
• Web of Science Citations: 0

Abstract

The glycocalyx is a highly hydrated, glycoprotein-rich coat shrouding many eukaryotic and prokaryotic cells. The intestinal epithelial glycocalyx, comprising glycosylated transmembrane mucins, is part of the primary host-microbe interface and is essential for nutrient absorption. Its disruption has been implicated in numerous gastrointestinal diseases. Yet, due to challenges in preserving and visualizing its native organization, glycocalyx structure-function relationships remain unclear. Here, we characterize the nanoarchitecture of the murine enteric glycocalyx using freeze-etching and electron tomography. Micrometer-long mucin filaments emerge from microvillar-tips and, through zigzagged lateral interactions form a three-dimensional columnar network with a 30nm mesh. Filament-termini converge into globular structures similar to 30nm apart that are liquid-crystalline packed within a single plane. Finally, we assess glycocalyx deformability and porosity using intravital microscopy. We argue that the columnar network architecture and the liquid-crystalline packing of the filament termini allow the glycocalyx to function as a deformable size-exclusion filter of luminal contents. Sun, Krystofiak et al. show the nanoarchitecture of the murine enteric glycocalyx, glycoprotein-rich coat covering cells and assess its porosity and deformability in mice, providing a comprehensive structural framework. This study suggests that the glycocalyx may function as a deformable size-exclusion filter of luminal contents. (AU)

• FAPESP's process: 13/22816-2 - Structural and cytochemical changes that precede, escort and succeed the irreverssible permeabilization of the inner mitochondrial membrane in apoptotic HeLa, COS-7 and PC-12 cells. a microscopic and cytometric study
• Grantee: Antonio Sesso
• Support Opportunities: Regular Research Grants